Mercury isotopes (Hg, Z = 80) — complete ground‑state set

Notation. Nuclides are written with the mass number as a left superscript (e.g., ²⁰³Hg).
Columns. Stable? is for the ground state (Obs.-stable = no decay observed). Half‑lives are the best‑evaluated values; # marks values partly inferred from trends near the drip lines. Decay → daughter(s) lists dominant branch(es); Radiation summarizes β⁺/β⁻/EC/α/p (proton) or n (delayed neutron). Origin sketches typical production; Uses flags M (medical), I (industrial), R (research).
Primary data spine: the evaluated Isotopes of mercury table. (Wikipedia)


Table — ground states

NuclideZAStable?Half‑lifeDecay → daughter(s)RadiationOrigin (typical)Uses / notes
¹⁷⁰Hg80170No≈ 310 µs (#)α → ¹⁶⁶PtαFusion‑evaporationR. (Wikipedia)
¹⁷¹Hg80171No≈ 70 µs (#)α → ¹⁶⁷PtαFusion‑evaporationR. (Wikipedia)
¹⁷²Hg80172No231 µsα → ¹⁶⁸PtαFusion‑evaporationR. (Wikipedia)
¹⁷³Hg80173No≈ 800 µs (#)α → ¹⁶⁹PtαFusion‑evaporationR. (Wikipedia)
¹⁷⁴Hg80174No2.0 msα → ¹⁷⁰PtαFusion‑evaporationR. (Wikipedia)
¹⁷⁵Hg80175No10.2 msα → ¹⁷¹PtαFusion‑evaporationR. (Wikipedia)
¹⁷⁶Hg80176No20.3 msα ≈ 90% → ¹⁷²Pt; β⁺ ≈ 10% → ¹⁷⁶Auα; β⁺Fusion‑evaporationR. (Wikipedia)
¹⁷⁷Hg80177No117 msα → ¹⁷³PtαFusion‑evaporationR. (Wikipedia)
¹⁷⁸Hg80178No266.5 msα ≈ 89% → ¹⁷⁴Pt; β⁺ ≈ 11% → ¹⁷⁸Auα; β⁺Fusion‑evaporationR. (Wikipedia)
¹⁷⁹Hg80179No1.05 sα ≈ 75% → ¹⁷⁵Pt; β⁺ ≈ 25% → ¹⁷⁹Au; β⁺,p 0.15% → ¹⁷⁸Ptα; β⁺; pFusion‑evaporationR. (Wikipedia)
¹⁸⁰Hg80180No2.59 sβ⁺ ≈ 52% → ¹⁸⁰Au; α ≈ 48% → ¹⁷⁶Ptβ⁺; αFusion‑evaporationR. (Wikipedia)
¹⁸¹Hg80181No3.6 sβ⁺ ≈ 73% → ¹⁸¹Au; α ≈ 27% → ¹⁷⁷Pt (β⁺p 0.014% → ¹⁸⁰Pt)β⁺; α; p(tr.)Fusion‑evaporationR. (Wikipedia)
¹⁸²Hg80182No10.83 sβ⁺ 86.2% → ¹⁸²Au; α 13.8% → ¹⁷⁸Ptβ⁺; αFusion‑evaporationR. (Wikipedia)
¹⁸³Hg80183No9.4 sβ⁺ 88.3% → ¹⁸³Au; α 11.7% → ¹⁷⁹Ptβ⁺; αFusion‑evaporationR. (Wikipedia)
¹⁸⁴Hg80184No30.87 sβ⁺ 98.89% → ¹⁸⁴Au; α 1.11% → ¹⁸⁰Ptβ⁺; αActivation / FER. (Wikipedia)
¹⁸⁵Hg80185No49.1 sβ⁺ 94% → ¹⁸⁵Au; α 6% → ¹⁸¹Ptβ⁺; αActivationR. (Wikipedia)
¹⁸⁶Hg80186No1.38 minβ⁺ 99.98% → ¹⁸⁶Au (α 0.016% → ¹⁸²Pt)β⁺; α(tr.)ActivationR. (Wikipedia)
¹⁸⁷Hg80187No1.9 minβ⁺ → ¹⁸⁷Auβ⁺ (γ)ActivationR. (Wikipedia)
¹⁸⁸Hg80188No3.25 minβ⁺ → ¹⁸⁸Au (α 3.7×10⁻⁵%)β⁺ (γ); α(tr.)ActivationR. (Wikipedia)
¹⁸⁹Hg80189No7.6 minβ⁺ → ¹⁸⁹Auβ⁺ (γ)ActivationR. (Wikipedia)
¹⁹⁰Hg80190No20.0 minβ⁺ → ¹⁹⁰Auβ⁺ (γ)ActivationR. (Wikipedia)
¹⁹¹Hg80191No≈ 49 minβ⁺ → ¹⁹¹Auβ⁺ (γ)ActivationR. (Wikipedia)
¹⁹²Hg80192No4.85 hEC → ¹⁹²AuX/γ (EC)ActivationR. (Wikipedia)
¹⁹³Hg80193No3.80 hβ⁺ → ¹⁹³Auβ⁺ (γ)ActivationR. (Wikipedia)
¹⁹⁴Hg80194No≈ 447 yEC → ¹⁹⁴AuX/γ (EC)Spallation (ISOLDE), activationR: long‑lived tracer; recommended value ~447 y, with historical measurements spanning 367–520 y. (Wikipedia, De Gruyter Brill, KAERI Nuclear Data Center)
¹⁹⁵Hg80195No10.69 hβ⁺ → ¹⁹⁵Auβ⁺ (γ)ActivationR. (Wikipedia)
¹⁹⁶Hg80196Obs.-stableNatural (0.15%)Enrichment target for ¹⁹⁷Hg/¹⁹⁷ᵐHg via (n,γ) and cyclotron routes. (NIST, ScienceDirect)
¹⁹⁷Hg80197No64.14 hEC → ¹⁹⁷AuX/γ (EC)Activation: ¹⁹⁶Hg(n,γ); cyclotron via Au(p,xn)M/R: classic renal/brain radiopharm (¹⁹⁷Hg‑chlormerodrin); paired ¹⁹⁷ᵐHg/¹⁹⁷Hg explored as theranostic. (IAEA Nuclear Data Services, Journal of Nuclear Medicine, RSNA Publications, PMC)
¹⁹⁸Hg80198Obs.-stableNatural (9.97%)Stable isotope; enrichment target in activation studies. (NIST)
¹⁹⁹Hg80199Obs.-stableNatural (16.87%)R: NMR‑active (I = 1/2); ultra‑precise magnetometers & EDM searches set **
²⁰⁰Hg80200Obs.-stableNatural (23.10%)Stable. (NIST)
²⁰¹Hg80201Obs.-stableNatural (13.18%)NMR‑active (I = 3/2), less favored vs ¹⁹⁹Hg for high‑resolution NMR. (Wikipedia)
²⁰²Hg80202Obs.-stableNatural (29.86%)Most abundant stable Hg. (NIST)
²⁰³Hg80203No46.610 dβ⁻ → ²⁰³Tlβ⁻ (γ 279 keV)Activation: ²⁰²Hg(n,γ)I/R: γ‑standard (279 keV) & radiotracer; well‑characterized decay for detector calibration. (Lnhb, EZAG Holding)
²⁰⁴Hg80204Obs.-stableNatural (6.87%)Stable. (NIST)
²⁰⁵Hg80205No5.14 minβ⁻ → ²⁰⁵Tlβ⁻ (γ)Fragmentation/activationR. (Wikipedia)
²⁰⁶Hg80206No8.32 minβ⁻ → ²⁰⁶Tlβ⁻ (γ)Fragmentation (trace natural via U‑series, rare)R. (Wikipedia)
²⁰⁷Hg80207No2.9 minβ⁻ → ²⁰⁷Tlβ⁻ (γ)FragmentationR. (Wikipedia)
²⁰⁸Hg80208No135 sβ⁻ → ²⁰⁸Tlβ⁻ (γ)FragmentationR. (Wikipedia)
²⁰⁹Hg80209No6.3 s (#)β⁻ → ²⁰⁹Tlβ⁻FragmentationR. (Wikipedia)
²¹⁰Hg80210No64 s (#)β⁻ 97.8% → ²¹⁰Tl; β⁻,n 2.2% → ²⁰⁹Tlβ⁻; n (delayed)FragmentationR. (Wikipedia)
²¹¹Hg80211No26.4 s (#)β⁻ 93.7% → ²¹¹Tl; β⁻,n 6.3% → ²¹⁰Tlβ⁻; nFragmentationR. (Wikipedia)
²¹²Hg80212No≈ 30 s (#)(likely β⁻ → ²¹²Tl)β⁻FragmentationR. (Wikipedia)
²¹³Hg80213No≈ 15 s (#)(likely β⁻ → ²¹³Tl)β⁻FragmentationR. (Wikipedia)
²¹⁴Hg80214No≈ 8 s (#)(likely β⁻ → ²¹⁴Tl)β⁻FragmentationR. (Wikipedia)
²¹⁵Hg80215No≈ 600 ms (#)(likely β⁻ → ²¹⁵Tl)β⁻FragmentationR. (Wikipedia)
²¹⁶Hg80216No≈ 2 s (#)(likely β⁻ → ²¹⁶Tl)β⁻FragmentationR. (Wikipedia)

Primary table source (half‑lives/branches/daughters): Isotopes of mercury (NUBASE/ENSDF‑based listing). (Wikipedia)


Natural isotopic composition (terrestrial Hg — NIST)

Stable nuclides and mole fractions: ¹⁹⁶Hg 0.0015, ¹⁹⁸Hg 0.0997, ¹⁹⁹Hg 0.1687, ²⁰⁰Hg 0.2310, ²⁰¹Hg 0.1318, ²⁰²Hg 0.2986, ²⁰⁴Hg 0.0687. Standard atomic weight Aᵣ°(Hg) = 200.592(3) (abridged 200.59). (NIST)


Selected isomers (high‑leverage)

  • ¹⁹⁷ᵐHgt½ = 23.82 h; IT ≈ 94.7% → ¹⁹⁷Hg, EC ≈ 5.3% → ¹⁹⁷Au. Produced efficiently from Au with low‑energy protons; investigated as a theranostic pair with ¹⁹⁷Hg. (Wikipedia, ScienceDirect)
  • ¹⁹⁹ᵐHgt½ = 42.67 min, IT → ¹⁹⁹Hg; used in nuclear‑structure level studies (γ cascades). (Wikipedia)

Applied & research highlights

  • Calibration & metrology. ²⁰³Hg (46.61 d, β⁻) has a clean 279.2 keV γ line; it is widely used as a γ‑ray detector calibration standard and in tracer studies. (Lnhb, EZAG Holding)
  • Nuclear medicine (historical & R&D). ¹⁹⁷Hg/¹⁹⁷ᵐHg labeled chlormerodrin (Neohydrin) was a workhorse for renal/brain scintigraphy in the 1960s–70s; the pair is now of interest as an imaging/therapy theranostic system. (RSNA Publications, Journal of Nuclear Medicine, PMC)
  • Precision physics. Enriched ¹⁹⁹Hg (spin 1/2) underpins high‑precision magnetometers and the world‑leading atomic EDM limit |d(¹⁹⁹Hg)| < 7.4×10⁻³⁰ e·cm; it also serves as a co‑magnetometer in neutron EDM experiments. (Physical Review, ScienceDirect)
  • NMR. Both ¹⁹⁹Hg (I = 1/2) and ²⁰¹Hg (I = 3/2) are NMR‑active; ¹⁹⁹Hg is preferred for high‑resolution work. (Wikipedia)

Totals — Mercury (Z = 80)

  • Ground‑state isotopes listed47 (A = 170–216, inclusive). (Wikipedia)
  • Stable (ground states)7 (¹⁹⁶, ¹⁹⁸, ¹⁹⁹, ²⁰⁰, ²⁰¹, ²⁰², ²⁰⁴). (Wikipedia)
  • Unstable (ground states)40. (Wikipedia)

Running cumulative totals (through Hg):
From Au running ledger (≥2518 total, 238 stable, ≥2279 unstable), add +47 total / +7 stable / +40 unstable≥2565 total, 245 stable, ≥2319 unstable.


Sources (load‑bearing)

  • Comprehensive isotope list, half‑lives, decay branches & daughters: Isotopes of mercury page (NUBASE/ENSDF backbone). (Wikipedia)
  • Isotopic composition & atomic weight: NIST PML Atomic Weights and Isotopic Compositions — Mercury. (NIST)
  • ¹⁹⁷Hg decay data (and γ‑lines) — safeguards/ENSDF standardization: IAEA Nuclear Data for Safeguards (D1/D2 tables). (IAEA Nuclear Data Services)
  • ¹⁹⁷ᵐHg / ¹⁹⁷Hg theranostics & production from Au: Walther et al. (2015) & Freudenberg et al. (2018). (ScienceDirect, PMC)
  • ²⁰³Hg decay scheme/γ standard: LNHB data sheet; EZAG recommended decay data. (Lnhb, EZAG Holding)
  • ¹⁹⁹Hg EDM limit & comagnetometer usage: PRL 2016; precision magnetometry literature. (Physical Review, ScienceDirect)

Next element: Thallium — Tl (Z = 81).

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